This invention relates to a patient airway bite block of the general type used together with laryngeal mask airways (LMAs), oral endotracheal tubes (ETTs) and similar patient airways. A patient under general anesthesia must have the airway maintained in an open position in order to assure adequate ventilation. This is most often accomplished by intubating the patient using an LMA or an ETT. The LMA can serve in place of either a patient facemask or an endotracheal tube and constructed with a distal portion, which is a cuffed disc, which fits around the patient's larynx in the posterior hypopharynx and a more proximal element, which is analogous to an endotracheal tube. LMAs are placed in anesthetized patients blindly and the exiting tube portion is positioned directly in the mid-line of the mouth.
Use of an LMA or an ETT in an anesthetized patient, requires a protocol that assures that the patient's airway remains open and thus requires that certain events be avoided. First, the patient may bite down on the airway tube and cause airway obstruction. This can lead very quickly to hypoxemia (i.e., dangerously low levels of oxygen in the blood). Second, biting by the patient's incisors can cause actual severing of the LMA or ETT and subsequent loss of control of the airway. Third, secretions tend to accumulate in the back of the throat during general anesthesia because there is a loss of the normal swallowing reflex in the anesthetized patient. In a lightly anesthetized patient or in a patient that is awakening from general anesthesia, such secretions can cause laryngospasm and subsequent airway closure. Therefore, it is best to keep the teeth apart with the soft bite block to allow these secretions to be suctioned from the mouth. Because of the above-described problems encountered using an LMA or an ETT, a bite block placed between the teeth of the anesthetized patient is necessary.
Conventional oral airways, which are usually used in patients anesthetized with their airway secured with oral endotracheal tubes, are not suitable for use with LMAs because such devices seat themselves directly in the mid-line of the mouth and thus, compete for the space where the tube portion of the LMA exits in the mouth. In addition, the posterior portion of the oral airway, which is used to hold the tongue forward when used with an endotracheal tube, impinges on the cuffed portion of the LMA in the hypopharynx resulting in the cuff not functioning properly. Among the solutions, practitioners have employed to provide bite blocks for patients with LMAs include the modification of other products, which are intended for completely different uses. For example, a bite guard for use with gastroscopy patients has been described for use as a bite block. This device is not suitable for use with an LMA because (1) it is not designed for use with LMAs and is not sized appropriately, (2) it seats in the center of the mouth and (3) it is not safe for patients with frontal dental bridgework since this is the area that will bite down on the device.